MagneSensors' program is aimed at developing a novel magnetocardiography (MCG) instrument that uses magnetic sensors for the rapid, non-invasive detection of cardiac ischemia. The proposed MCG instrument takes advantage of ultra-sensitive superconducting quantum interference devices (SQUIDs) to detect the magnetic fields generated by electrical activity in the heart. The program will use innovative high temperature (high-Tc) SQUID technology to produce the portable, lower cost instruments that are necessary for widespread clinical application. Chest pain is the second leading cause of admission in emergency rooms in the U.S and the costs associated with ruling out acute myocardial infarction (AMI) exceeds $3 billion. Existing techniques such as biomarker blood tests and electrocardiography (ECG) are inadequate and unable to prevent adverse outcomes of missed AMI and the huge costs of unnecessary hospitalization. The U.S. market for MCG instrumentation is estimated at near $1 billion in the emergency department alone. Recent published studies have laid the groundwork for the application of MCG to the detection of cardiac ischemia. The presence of ischemic tissue shows up as abnormalities on two-dimensional magnetic field maps produced by MCG. New algorithms have shown that MCG can achieve a high negative predictive value, which is essential for ruling out AMI. The Phase I effort focuses on demonstrating that high-Tc SQUID sensors can be operated in an "unshielded" environment with sufficient sensitivity to detect the necessary cardiac signals. Since the data analysis can use averaged MCG waveforms, the ultimate in SQUID sensitivity is not required. Unshielded measurements of MCG data taken with high-Tc sensors will be compared with MCG data from conventional low-Tc systems to demonstrate that the signal-to-noise of high-Tc sensors is sufficient for detection. Phase I is aimed developing a proof-of-concept capability to justify a Phase II program to build a portable MCG instrument for clinical use and to examine patients in the emergency department. [unreadable] [unreadable] [unreadable]